Process for coloring polyester shaped articles

A process is provided for the coloration of a preformed polyester resin shaped article having improved dye migration properties, which comprises: (a) coloring said article with a coloring agent in an amount sufficient to provide coloration to said shaped article; said coloring agent having the formula wherein R is an organic dyestuff radical; the polymeric constituent is selected from polyalkylene oxides and copolymers of polyalkylene oxides in which the alkylene moiety of the polymeric constituent contains 2 or more carbon atoms and such polymer constituent has a molecular weight of from about 132 to about 500; and n is an integer of fromm 1 to about 12; and X is selected from -OH, -NH2, -SH, -OCORi, -C02H, -CO2R1, -S03H, -S03Rl phosphate, phosphonite, urea, urethane, alkoxyl and alkoxide, wherein R1 is a lower alkyl group containing from 1 to about 6 carbon atoms; and(b) grafting said coloring agent to said article by heating said article to a temperature below a temperature at which said article will melt, but to a high enough temperature and for a period of time sufficient to achieve grafting of said coloring agent to said article.